With more options come more decisions. With equivalence testing added to Minitab 17, you now have more statistical tools to test a sample mean against target value or another sample mean.

Equivalence testing is extensively used in the biomedical field. Pharmaceutical manufacturers often need to test whether the biological activity of a generic drug is equivalent to that of a brand name drug that has already been through the regulatory approval process.

But in the field of quality improvement, why might you want to use an equivalence test instead of a standard t-test?

Interpreting hypothesis tests: A common pitfall

Suppose a manufacturer finds a new supplier that offers a less expensive material that could be substituted for a costly material currently used in the production process. This new material is supposed to be just as good as the material currently used. It should not make the product too pliable or too rigid.

To make sure the substitution doesn’t negatively affect quality, an analyst collects two random samples from the production process (which is stable): one using the new material, and one using the current material.

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